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K Ariyoshi

Publications and source records attributed to K Ariyoshi.

At least 19 recordsLinked to original sources
PubMed2006

Bayesian network analysis of resistance pathways against HIV-1 protease inhibitors.

Interpretation of Human Immunodeficiency Virus 1 (HIV-1) genotypic drug resistance is still a major challenge in the follow-up of antiviral therapy in infected patients. Because of the high degree of HIV-1 natural variation, complex interactions and stochastic behaviour of evolution, the role of resistance mutations is in many cases not well understood. Using Bayesian network learning of HIV-1 sequence data from diverse subtypes (A, B, C, F and G), we could determine the specific role of many resistance mutations against the protease inhibitors (PIs) nelfinavir (NFV), indinavir (IDV), and saquinavir (SQV). Such networks visualize relationships between treatment, selection of resistance mutations and presence of polymorphisms in a graphical way. The analysis identified 30N, 88S, and 90M for nelfinavir, 90M for saquinavir, and 82A/T and 46I/L for indinavir as most probable major resistance mutations. Moreover we found striking similarities for the role of many mutations against all of these drugs. For example, for all three inhibitors, we found that the novel mutation 89I was minor and associated with mutations at positions 90 and 71. Bayesian network learning provides an autonomous method to gain insight in the role of resistance mutations and the influence of HIV-1 natural variation. We successfully applied the method to three protease inhibitors. The analysis shows differences with current knowledge especially concerning resistance development in several non-B subtypes.

Bayes Theorem↗
PubMed2001

Impact of baseline polymorphisms in RT and protease on outcome of highly active antiretroviral therapy in HIV-1-infected African patients.

OBJECTIVE: To assess the therapeutic response and investigate the significance of polymorphic codons in African patients receiving highly-active antiretroviral therapy (HAART). DESIGN AND METHODS: African patients were identified from the St Mary's Hospital HIV-1 database. Clinical outcome was assessed by viral load and CD4 cell count. Pre- and post-therapy sequences of RT and protease were analysed. The impact of subtype and individual polymorphic codons on therapeutic outcome was assessed statistically (Fishers exact and chi2 tests) and phylogenetically (Jukes and Cantor). RESULTS: Of 79 drug-naive African patients who were prescribed HAART, 60 remained undetectable for 1 year, with no differences detected in the clinical response to non-nucleoside reverse transcriptase inhibitor (NNRTI)- or protease inhibitor (PI)-containing regimes. Country of origin, sex and viral subtype had no impact on outcome of HAART. A total of 133 polymorphisms were identified in pol (37 in protease and 96 in RT), with a mean of 9.0 in protease and 22.3 in RT per patient. There was no significant difference in the overall numbers of polymorphisms per patient, and no single polymorphism had any impact on clinical outcome. Sequences from 'failing' patients experiencing viral rebound produced few mutations known to be associated with drug resistance, suggesting minimal drug pressure. CONCLUSIONS: The response of patients infected with African subtypes of HIV-1 to HAART appears to be independent of regime, HIV-1 clade and baseline polymorphisms. Non-B subtypes are fully sensitive to HAART and, accordingly, therapy should not be withheld from African patients for reasons of viral diversity.

Africa↗
PubMed2001

Sequence specificity of the human immunodeficiency virus type 2 (hiv-2) long terminal repeat u3 region in vivo allows subtyping of the principal hiv-2 viral subtypes a and b.

Sequences from the nef/LTR overlap region of the human immunodeficiency virus type 2 (HIV-2) genome were amplified from uncultured peripheral blood mononuclear cells (PBMCs) from 40 HIV-2-infected individuals in The Gambia, West Africa. Additional sequences from the plasma of three blood donors were also derived. Analysis of HIV-2 U3 LTR transcription factor elements (PuB-1, p-ets, PuB-2, peri-kappa B, and NF-kappa B sites) indicated a relatively high level of conservation in vivo. The region immediately 3' of the nef termination codon, which exhibits clade-dependent specificity, was targeted by PCR to differentiate HIV-2 subtype A from subtype B infections, the two principal clinical HIV-2 subtypes. All clinical samples analyzed (n = 43) from The Gambia were identified as HIV-2 subtype A by a combination of LTR sequence analysis and subtype-specific amplification of subtypes A and B. Differential PCR amplification of the HIV-2 U3 LTR region represents a rapid means of differentiating subtype A from subtype B infections, the two dominant HIV-2 subtypes that are important in human disease.

Base Sequence↗
PubMed2000

Constitutive activation of STAT5 by a point mutation in the SH2 domain.

We previously identified a constitutively active form of STAT (signal transducer and activator of transcription) 5A by polymerase chain reaction-driven random mutagenesis followed by retrovirus-mediated expression screening, which had two point mutations in the DNA-binding and transcriptional activation domains, and was designated STAT5A1*6. STAT5A1*6 showed markedly elevated DNA binding and transactivation activities with stable tyrosine phosphorylation and nuclear accumulation, and conferred autonomous cell growth on interleukin 3-dependent Ba/F3 cells. We now report another constitutively active mutant, STAT5A-N642H which has a single point mutation (N642H) in its SH2 domain, identified using the same strategy as that used to identify STAT5A1*6. STAT5A-N642H showed identical properties to those of STAT5A1*6 both biochemically and biologically. Interestingly the mutation in STAT5A-N642H resulted in restoration of the conserved critical histidine which is involved in the binding of phosphotyrosine in the majority of SH2-containing proteins. Introduction of an additional mutation (Y694F) to STAT5A-N642H, which disrupted critical tyrosine 694 required for dimerization of STAT5, abolished all the activities manifested by the mutant STAT5A-N642H, which indicates that dimerization is required for the activity of STAT5A-N642H as was the case for the wild-type STAT5A. The present findings also show that different mutations rendered STAT5A constitutively active, through a common mechanism, which is similar to that of physiological activation.

3T3 Cells↗
PubMed2000

Plasma RNA viral load predicts the rate of CD4 T cell decline and death in HIV-2-infected patients in West Africa.

OBJECTIVE: To examine whether the levels of plasma RNA and DNA provirus predict the rate of CD4 cell decline and patient death. DESIGN: Retrospective analysis of HIV-2 cohort subjects. METHODS: Fifty-two subjects were recruited between January 1991 and December 1992. HIV-2 RNA levels in plasma and DNA levels in peripheral blood mononuclear cells (PBMC) were measured using in-house quantitative PCR assays. The annual rate of CD4 cell decline was calculated using the least-squares method. The survival data on 31 December 1997 were used. RESULTS: The mean percentage of CD4 cells at baseline was 30.7 (SD, 9.5). In a linear regression model, the annual rate of CD4 cell decline was 1.76 CD4% faster for every increase in one log10 RNA copies/ml [95% confidence interval (CI), 0.81-2.7; P = 0.0006; r = 0.46; n = 52] and 1.76 CD4% faster for every increase in log10 DNA copies/10(5) PBMC (95% CI 0.46-3.1; P = 0.01; r = 0.33; n = 42). In a multiple linear regression model, RNA load was related to CD4 decline independently of DNA load (P = 0.02). The overall mortality rate was 7.29/100 person-years. In a Cox regression model, the hazard rate increased by 2.12 for each log10 increase in RNA load (95% CI, 1.3-3.5; P = 0.0023) but only by 1.09 for each log10 increase in DNA load (95% CI, 0.64-1.87; P = 0.8). CONCLUSION: This longitudinal study shows for the first time that a baseline HIV-2 RNA load predicts the rate of disease progression. HIV-2-infected patients with a high viral load may need to be treated as vigorously as HIV-1 patients.

Adolescent↗
PubMed2000

Maternal HIV-1 and HIV-2 infection and child survival in The Gambia.

OBJECTIVE: To compare the survival of children born to HIV-1 or HIV-2 seropositive mothers with that of children born to HIV-seronegative mothers and to evaluate risk factors for mortality. DESIGN: Physician-blinded prospective study. METHODS: One hundred and one HIV-1-seropositive, 243 HIV-2-seropositive pregnant women, and 468 HIV-seronegative women (control group) matched by age, parity, and health centre, were followed up in a study of mother-to-child transmission of HIV. Mothers and children were seen at 2 and 6 months of age and subsequently followed at 3-monthly intervals up to 18 months of age. HIV infection in children was diagnosed by polymerase chain reaction at 2, 9 or 18 months and by antibody assays at 18 months. RESULTS: Fifteen per cent of children born to HIV-1-infected mothers died compared with 7% of children born to HIV-2-infected mothers [hazard ratio, 2.3; 95% confidence interval (CI), 1.1-4.7; P = 0.02], and 6% of HIV-seronegative mothers (hazard ratio, 2.6; 95% CI, 1.4-5.0; P = 0.003). Six of the 17 children known to be HIV-1 infected died compared with none among the eight HIV-2-infected children (P = 0.13). High proviral load in the babies, high antenatal maternal RNA plasma viral load, and maternal death increased child mortality significantly. CONCLUSIONS: More children born to HIV-1-infected mothers died in comparison with those born to HIV-2-infected mothers or to mothers from the control group. This effect was due to excess death in HIV-1-infected infants which was associated with a high viral load in the affected mother and child.

Female↗
PubMed2000

Maternal plasma viral RNA levels determine marked differences in mother-to-child transmission rates of HIV-1 and HIV-2 in The Gambia. MRC/Gambia Government/University College London Medical School working group on mother-child transmission of HIV.

OBJECTIVES: To determine the rates of, and risk factors for, mother-to-child transmission (MCT) of HIV-1 and HIV-2 infection in The Gambia. DESIGN: A blinded, prospective, community-based cohort study of 29.549 pregnant women attending the eight largest antenatal clinics in The Gambia. METHODS: Women were tested for HIV-1 and HIV-2 infection. Infected subjects and a group of HIV-seronegative women were followed with their babies until 18 months after delivery. Maternal CD4 cell count percentages were measured before and 18 months after delivery, and the antenatal plasma viral load was determined. Babies were tested for HIV by the polymerase chain reaction and/or serology at 2, 9 and 18 months of age. RESULTS: The study enrolled 144 women positive for HIV-1 and 294 for HIV-2 plus 565 seronegative pregnant women: the mean antenatal percentage CD4 cell counts of 96 HIV-1-positive, 223 HIV-2-positive and 125 HIV-seronegative mothers were 31% [95% confidence interval (CI) 28-33], 41% (95% CI 39-42) and 47% (95% CI 45-49), respectively. The geometric mean antenatal plasma viral load of 94 HIV-1-infected women was 15,100 copies x 10(3) ml (95% CI 10,400-19,000) which was much higher than that of 60 randomly selected HIV-2-infected women, which was 410 copies x 10(3) ml (95% CI 150-910) (P < 0.001). The estimated transmission rate of HIV-1 was 24.4% (95% CI 14.6-33.9) and that of HIV-2 was 4.0% (95% CI 1.9-7.4). Five of 17 HIV-1-positive and three of eight HIV-2-positive babies were infected after 2 months of age. Birth in the rainy season [odds ratio (OR) 2.9; 95% CI 1.2-7.2], a low postnatal CD4 cell percentage (OR for a 10% fall 2.4; 95% CI 1.1-5.1) and a high maternal plasma viral load (OR for a 10-fold increase 2.9; 95% CI 1.1-7.8) were risk factors for transmission that applied equally to both viruses. CONCLUSION: Low maternal HIV-2 RNA levels, which on average are 37-fold less than in HIV-1 infection, relate to the low MCT rate of HIV-2.

CD4 Lymphocyte Count↗
PubMed2000

Ovarian endometriosis associated with ovarian carcinoma: a clinicopathological and immunohistochemical study.

OBJECTIVE: The purpose of this study was to demonstrate the incidence, the histopathological characteristics, and the proliferation activity of endometriosis and atypical endometriosis associated with ovarian carcinoma. METHODS: Microscopic slides of primary lesions from 127 patients with primary ovarian carcinoma were reviewed. The presence or absence of endometriosis and the transitions from typical endometriosis to atypical endometriosis and from atypical endometriosis to carcinoma were also histologically evaluated. Ki-67 immunoreactivity of typical and atypical endometriosis and carcinoma was examined. In addition, endometrial metaplasias were also evaluated. RESULTS: Of the 127 patients, 37 had endometriosis: 70% (30/43) had clear cell adenocarcinoma, 43% (3/7) had endometrioid adenocarcinoma, 7% (4/60) had serous adenocarcinoma, and none (0/17) had mucinous adenocarcinoma. Thirty-three cases showed typical endometriosis and 29 cases had atypical endometriosis (25 cases had both). Tufting and the stratification of the lining epithelium were observed in 25 and 23 cases, respectively. The transition from typical endometriosis to atypical endometriosis was observed in 22 cases, and the transition from atypical endometriosis to carcinoma, in 23 cases. Only one case showed a direct transition from typical endometriosis to carcinoma. The mean Ki-67 indices were as follows: ovarian carcinoma, 23.1; atypical endometriosis, 9.9; typical endometriosis, 2.7. In 18 cases with metaplasia in endometriosis, eosinophilic metaplasia and ciliated metaplasia were the most common types. Five cases had two types of metaplasia. CONCLUSIONS: Ovarian carcinomas, especially clear cell and endometrioid adenocarcinomas, are highly associated with endometriosis. Atypical endometriosis shows proliferation activity intermediate to those of typical endometriosis and ovarian carcinoma, suggesting it is a precancerous status.

Adenocarcinoma, Clear Cell↗
PubMed2000

Prognostic factors in ovarian carcinosarcoma: a clinicopathological and immunohistochemical analysis of 23 cases.

UNLABELLED: Carcinosarcoma of the ovary is a rare, highly aggressive neoplasm comprising histologically of both epithelial and mesenchymal components. The aim of this study was to evaluate the clinicopathological prognostic factors in ovarian carcinosarcoma, including the immunohistochemical expression of p53 protein and Ki67. METHODS AND RESULTS: Twenty-three cases of carcinosarcoma of the ovary were studied retrospectively. The clinicopathological and immunohistochemical parameters including p53 and Ki67 staining were statistically analysed to investigate the prognostic significance of this tumour. The overall 5-year survival rate was 27.1%; 100% for stage I, 31.3% for stage II, 10.9% for stage III and 0% for stage IV. The low-stage group (stages I and II) was found to be a significant prognostic factor for patient survival (P = 0.0113). None of the other factors (tumour size, histological type of carcinomatous and sarcomatous components, mitotic count, vascular space invasion and immunoreactivity for p53 protein and Ki6 7) was found to be a statistically significant prognostic indicator. CONCLUSIONS: Ovarian carcinosarcoma is a rare malignancy with poor prognosis. In this study, advanced stage appears to be poor prognostic indicator of survival in patients with ovarian carcinosarcoma.

Adult↗
PubMed2000

Chronic neutrophilic leukemia with acute myeloblastic transformation.

We report a rare case of chronic neutrophilic leukemia (CNL) which terminated in acute myeloblastic transformation 3 years after the onset of the disease. The increased leukocytes were mainly neutrophils at various maturational stages until 1 month before transformation without dysplastic hematopoietic cells or other myeloproliferative disorders. Repeated analyses for the Philadelphia chromosome (Ph1), rearrangement of the BCR gene or chimeric BCR/ABL mRNA, major, minor and mu, were negative. Genomic analysis of granulocyte colony-stimulating factor (G-CSF) receptor did not reveal any abnormality. The clinical manifestations were characterized by hyperleukocyte syndrome with respiratory distress and ischemic legs with gangrene.

Aged↗
PubMed2000

Constitutively active STAT5A and STAT5B in vitro and in vivo: mutation of STAT5 is not a frequent cause of leukemogenesis.

We recently identified several constitutively active forms of signal transducers and activators of transcription 5 (STAT5) using polymerase chain reaction-driven random mutagenesis followed by retrovirus-mediated expression screening. All constitutively active STAT5 showed constitutive phosphorylation on their tyrosine residues and induced factor-independent growth in a mouse interleukin-3-dependent cell line, Ba/F3. Sequence analysis of these active STAT5 revealed two important mutations: S710F and N642H. The N642H mutation localized in the SH2 domain was able to induce autonomous growth of Ba/F3 cells by itself, whereas S710F in the effector domain was able to induce autonomous growth of Ba/F3 cells in concert with a second mutation including H298R and E150G. Recently, constitutive activation of STAT5 has been reported in patients' leukemic cells and is implicated in leukemogenesis. We attempted to clarify whether leukemic cells harbored activating mutations primarily in STAT5 proteins, and analyzed the sequence of STAT5 derived from 49 leukemic patients. No mutations were found, however, in the regions surrounding S710 and N642 of STAT5A and corresponding residues of STAT5B. We also cloned full-length cDNAs for STAT5s from three patients whose leukemic cells exhibited constitutive tyrosine phosphorylation of the STAT5 protein and expressed the derived STAT5 proteins in Ba/F3 cells. However, none of these clones exhibited constitutive tyrosine phosphorylation or gave rise to FI proliferation of Ba/F3 cells. These results indicate that constitutive activation of STAT5 is a secondary event in most leukemias.

Animals↗
PubMed2000

Morphological and cytogenetic changes in therapy-related leukemia developed in a t(8;21)-acute myeloid leukemia (M2) patient: sequential cytogenetic and molecular analyses.

A patient with acute myeloid leukemia (AML)-M2 with t(8;21)(q22;q22) achieved complete remission with remission-induction chemotherapy followed by consolidation and intensification chemotherapies. T(8;21)(q22;q22) disappeared, but chimeric AML1/MTG8 was continuously detected in bone marrow cells. Following the development of therapy-related leukemia after 1 year, evolution of therapy-related AML-M4 with t(11;17)(q23;q25) and the rearrangement of the MLL gene were observed, while AML/MTG8 disappeared. After reinduction and following intermittent chemotherapies, a subsequent alternative transformation to AML-M2 occurred after detection of t(3;21)(q21;q22), with a break in the AML1 gene shown by interphase fluorescence in situ hybridization analysis. This leukemia transformed to AML-M4 after t(9;22)(q34;q11), with a minor BCR/ABL rearrangement, and then finally to AML-M2. This therapy-related leukemia was resistant to chemotherapy. These findings indicate that alterations in cytogenetic and molecular events caused by chemotherapeutic agents contribute to the sequential evolution of new leukemic clones with different morphology.

Adult↗
PubMed1999

Variability and evolution of Kaposi's sarcoma-associated herpesvirus in Europe and Africa. International Collaborative Group.

OBJECTIVE: To study the evolution of Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus type 8 in Europe and Africa. DESIGN AND METHODS: PCR and sequence analysis of the variable viral membrane glycoprotein gene K1 in 58 tumour and peripheral blood samples from patients with AIDS-related Kaposi's sarcoma (KS), 'classic' (HIV-negative) KS, transplant KS, Multicentric Castleman's Disease, other lymphoproliferative disorders, and healthy KSHV-infected individuals from the UK, Denmark, Sweden, Italy, Spain, Iceland, The Faroe Islands, Greece, The Gambia and Uganda. RESULTS: Three major groups of K1 sequences were found: A, B and C, as defined previously. The K1 gene has evolved, both within and between these three groups, under positive selection. KSHV group B strains predominate in Africa and are more distant from groups A and C, found in Europe, than A and C are from each other. Within group C two subgroups, C' and C", can be identified. Subgroup C" is more closely related to group A in a region of the K1 protein and appears to be phylogenetically close to the branchpoint between A and C. Group A and C strains are currently found in both HIV-1-infected and -uninfected Europeans, and were already present in Europe before the start of the AIDS epidemic. We found some examples of closely related K1 sequences in Italy and Denmark, but in general KSHV strains in Europe did not cluster geographically. CONCLUSION: KSHV strains in East and West Africa are closely related but phylogenetically distant from those in Europe. The two major KSHV groups in Europe are more closely related, with some strains adopting an intermediate phylogenetic position. In Europe, KSHV strains may have been disseminated at least several decades ago. Variability in the K1 region is driven by selection and does not correlate with different KSHV-related pathologies or geographic regions where clinically more aggressive HIV-negative KS ('endemic' KS) is more common.

AIDS-Related Opportunistic Infections↗
PubMed1999

Comparison of p53, Ki-67, and CD44v6 expression between primary and matched metastatic lesions in ovarian cancer.

OBJECTIVE: Many studies have demonstrated that clinically evident tumor cells already carry multiple genetic alterations and further accumulation of genetic alteration causes tumor progression which plays a role in metastasis. Therefore, it could be expected that malignant potential in the metastatic site is more aggressive than that in the primary site. Using several immunohistochemical markers (p53, Ki-67, and CD44v6), we investigated an alteration of malignant potential. METHODS: We immunohistochemically examined expression of p53, Ki-67, and CD44 in primary and metastatic lesions of ovarian cancer. Fifty-six samples of primary lesions and matched metastatic sites from 56 patients with primary epithelial ovarian cancers were included in this study. RESULTS: In 16 cases (28%), the histological grade of the metastatic lesion increased. This difference was statistically significant (P = 0.0232). In 16 cases (28%), the expression of p53 increased in the metastatic lesions, in 5 pairs from negative to positive, whereas the case decrease in the metastatic lesions was only 1. This difference was statistically significant (P = 0.0046). There was no significant difference in Ki-67 labeling indices and expression of CD44v6 between the primary and matched metastatic lesions. The degree of p53 expression in the metastatic lesions significantly correlated with disease-free survival (P = 0.0482), whereas that in the primary lesions did not. Moreover, high p53 expression in the metastatic lesions significantly correlated with disease-free survival in multivariate analysis. CONCLUSIONS: The p53 expression in metastatic lesions may reflect an aggressive biologic behavior in ovarian cancer.

Adenocarcinoma↗
PubMed1999

Prognostic significance of epithelial-stromal vascular cuffing and microvessel density in squamous cell carcinoma of the uterine cervix.

OBJECTIVE: Tumor angiogenesis has been shown to play an important role in tumor growth and metastasis. This study examines the prognostic significance of two histological markers of angiogenesis, i.e., vascular cuffing (VC), a bead-like arrangement of microvessels closely surrounding microscopic tumor nests, and microvessel density (MVD), the number of microvessels in a unit area, in cervical squamous cell carcinoma. METHODS: One hundred twenty-two specimens from surgically resected uteri with cervical squamous cell carcinoma were histologically reviewed and immunostained for CD34. VC was graded into "none," "incomplete," and "complete." The MVD was determined by counting the microvessels with a light microscope within a x200 field area where neovascularization occurred most actively. Stromal inflammation was also split into three grades. The relationship of VC or MVD to clinicopathological prognostic factors such as FIGO stage, cervical stromal invasion, lymph-vascular space invasion, pelvic lymph node metastasis, and parametrial invasion was evaluated using univariate and multivariate analyses. RESULTS: The patients with a complete VC pattern showed a significantly worse prognosis compared to those with a pattern graded as either none or incomplete (P<0.011 and P<0.0001, respectively). The Cox regression analysis revealed the complete VC pattern, together with parametrial invasion, to be an independent prognostic indicator for overall survival. MVD and the grading of stromal inflammation showed no significant relationship with VC or overall survival. CONCLUSIONS: The complete VC pattern may therefore be a useful prognostic indicator in cervical squamous cell carcinoma.

Adult↗